Question Mark Galaxy, Rosse's Galaxy, M51a, NGC 5194, UGC 8493, PGC 47404, VV 001a, VV 403, Arp 85, GC 3572
M51 is a luminous spiral galaxy that is experiencing mass star birth. It is interacting with its neighboring galaxy NGC 5195, a smaller Lenticular galaxy that is considered part of the whirlpool galaxy.
The nucleus of the galaxy has an x-shaped structure. The main body has a very active core, similar in size to the Milky Way, and the dormant member of a small group of galaxies called the M51 Group that includes M63, the Sunflower Galaxy.